The present invention relates to a structured packing for producing intimate contact between vapor and liquid phases. More particularly, the present invention relates to such a structured packing formed of a plurality of juxtaposed sheets having corrugations to define fine flow channels. Even more particularly the present invention relates to such a structured packing in which a plurality of elongated projections are situated within the flow channels to produce turbulence in the vapor phase.
In many chemical process applications, for instance heat exchange, adsorption, distillation, it is necessary to bring liquid and vapor phases into contact with one another. Such contact is induced by various liquid-vapor contact media such as sieve plates, trays and structured packing. Structured packing has found increased use in process applications due to its predictable performance and its low pressure drop characteristics. Structured packing consists of a plurality of juxtaposed sheets having corrugations and can be obtained with various packing densities, angular relationships between the corrugations, and performance characteristics.
Structured packing is used in connection with a liquid distributor placed within a column and above the packing to distribute the liquid phase to the packing. The liquid phase descends within the structured packing as a falling film. At the same time, a vapor phase ascends in the column through vapor passages provided within the packing by the corrugations to cause intimate contact or mixing between the liquid and vapor phases.
Heat and mass transfer between the liquid and vapor phases occurs at the interface between the phases which is located close to the surface of the sheet material making up the structured packing. In the case of mass transfer, the transfer of a component from one phase to the other creates a concentration gradient in the vapor phase within each flow channel in a direction taken normal to the surface of the sheet material. As will be apparent to those skilled in the art, the rate of mass transfer between the phases will be higher when the vapor phase is of uniform concentration and will be lower once such a concentration gradient is established.
As will be discussed, the present invention provides a structured packing in which the vapor phase periodically undergoes turbulent mixing as it travels through the flow channels within the packing. This mixing inhibits the formation of concentration gradients in the vapor phase in a direction taken normal to the surface of the sheet material and thereby increases the rate of mass transfer between phases. A similar effect would be obtained in the case of heat transfer; the turbulence inhibits the formation of a temperature gradient and thereby increases the overall rate of heat transfer.